Modeling of a non-physical fish barrier

Transcription

1 University of Massachusetts - Amherst ScholarWorks@UMass Amherst International Conference on Engineering and Ecohydrology for Fish Passage International Conference on Engineering and Ecohydrology for Fish Passage 2014 Jun 9th, 3:50 PM - 4:10 PM Modeling of a non-physical fish barrier M. Politano University of Wisconsin - Madison Follow this and additional works at: Politano, M., "Modeling of a non-physical fish barrier" (2014). International Conference on Engineering and Ecohydrology for Fish Passage This Event is brought to you for free and open access by the The Fish Passage Community at UMass Amherst at ScholarWorks@UMass Amherst. It has been accepted for inclusion in International Conference on Engineering and Ecohydrology for Fish Passage by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact scholarworks@library.umass.edu.

2 MODELING OF A NON-PHYSICAL FISH BARRIER M. Politano and J. Martin. IIHR - Hydroscience & Engineering. The University of Iowa. Y. Lai and M. Bender. US Department of the Interior. Bureau of Reclamation. D. Smith. U.S. Army Corps of Engineers.

3 Introduction The migration of salmonids in the San Joaquin and Sacramento Rivers is of great environmental interest. Several fish species are listed are threatened or endangered under the California Endangered Species Act. Juveniles encounter alternative pathways during migration to the Pacific Ocean. Passage through the interior Delta decreased the survival of juveniles. Fish diversion into the Delta may result in delayed migration, elevated risk of predation, exposure to poor water quality conditions, and mortality in pumping facilities.

4 Behavioral Bio-Acoustic Fish Fence BAFF combines three stimuli to deter fish from entering an undesirable pathway without restricting flow: Bubble curtain Low-frequency sound LED modulated intensity lights

5 Objectives Develop bubble, sound and light models Implement the models into a CFD code using a modular approach pisofoambls Validate the model against several well-known experiments Simulate a BAFF to predict bubble, sound and light fields and evaluate effects of the barrier on the river hydrodynamics

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7 Bubble Module

8 Bubble Model Mixture model u m = 0 Re ρl um + ρl ( umum) = P+ τm + τ m + ρm g t Bubble number density Bubble velocity Gas volume fraction N t t ν + ug N = Sc D 2 3Cg P+ k + ur ur = R 2 N α = N mb ρ b

9 Bubble model predictions and experiments

10 Sound Model Classical formulation (Lighthill, 1978): wave equation based on compressible Navier-Stokes Equations: xx 2 cc ii tt 2 PP = ff ii + xx ii TT iiii ~ cc 2 2 PP h xx ii xx jj tt 2 Alternative formulation: energy formulation based on the acoustic energy W, the acoustic energy flux I and dissipation D WW = II DD The following relations are proposed to obtain an equation in W: II = DD WW WW; DD = σσ WW WW

11 Sound Model Diffusion and attenuation coefficients Diffusion coefficient based on architectural models (Picaut et al. 1999): Anisotropy related to length-scale of domain, an diffusion proportional to sound speed, with proportionality constant dependent on boundary reflectivity. DD WW = DD xxxx DD yyyy DD zzzz DD xxxx l xx = DD yyyy l yy = DD zzzz l zz = DD 3DD ~ cc Attenuation coefficient simplified model based on emission frequency, sound speed and void fraction σσ WW = ff ssssss ccαα (MKS, isothermal)

12 Validation of Sound Model Implementation A cube with 100 m on the side was simulated. A one m 3 sound source at the cube center and variable distribution of gas volume fraction were included. Isotropic diffusion tensor and length scale as the source dimension were used. Effect of diffusion parameter Effect of bubbles Effect of bubbly region Sound level with a sound source at the origin

13 Sound Model - Validation Experiments of Wusig et al. (2000): sound from a pile driving hammer in shallow water, with and without bubble curtain without bubble curtain with bubble curtain

14 Light Model Classical model : Radiative Transfer Equation Integro-differential equation, on position x and direction Ω is too expensive to solve numerically for the present application Ω LL xx, θθ, φφ, λλ = cc E xx, λλ LL xx, θθ, φφ, λλ + LL xx, θθ, φφ, λλ ββ ss xx, θθ, φφ, θθ, φφ, λλ ddω variation of spectral radiance L Alternatives models P-N models absorption aa E and scattering out bb E of beam Approximate direction dependence using orthogonal series of spherical harmonics Valid for high attenuation/scattering conditions Superposition of elementary solutions (planar, linear and point sources) Valid for low scattering conditions 4ππ scattering into beam + ss E xx, θθ, φφ, λλ external source

15 Light Model - P-1 model Simplest of P-N models. Radiance approximately by LL xx, φφ, θθ ~ 1 LL LL 1 cos φφ + LL 2 sin φφ cos θθ + LL 3 sin φφ sin θθ, 4ππ LL 0 = EE, the scalar irradiance Effectively results on diffusive-like equation for irradiance E, 3 1 EE xx ii 3 aa E + bb E xx ii ii=1 = 4ππss E aa E EE Valid for thick optical media, aa E + bb E l 1, with l a characteristic length-scale

16 Light Model: Superposition of elementary solutions Elementary solutions Planar source: EE(zz) = EE 0 exp( KKKK) Point source: EE rr = rr 0 2 EE rr 0exp KKKK 2 Elementary solutions can be represented numerically by solving uu EE EE = SS E KKKK, with imposed advective uu EE. Scattering by media cannot be modeled, only attenuation, valid for thin optical media Reflections from boundaries can be included if the reflection direction distribution is imposed and discretized Examples of possible boundary conditions are specular reflection Lambertian cosine law (diffuse reflection) Partial transmission

17 Light Model: Scattering and attenuation coefficients For modeling purposes it was assumed that all attenuation was caused by the water and dissolved solids and all scattering by the bubbles Attenuation coefficient KK DD = KK ww+dddddd + KK cc CC cc + KK ss CC TTTTTT Scattering coefficient Non-interacting (dilute) scatterers : cc dilute = 3 4 Interacting scatterers (VF > 8%): cc E = γγcc dilute, γγ = αα 3 4 αα2 αα RR

18 Validation of Light Model Implementation Closed Cavity Normal sunlight Sunlight with a zenith angle No reflection No attenuation Attenuation of radiation by medium Reflection Dimensionless Irradiance

19 Validation of Light Model Implementation Closed Cavity Normal sunlight No attenuation Point sources Dimensionless Irradiance

20 Validation of Light Model Implementation Contours of Irradiance with P1 Model Water-air interface Fully reflecting α = 0.01 α = 0.02 α = 0.01 α = 0.02 α = 0.05 α = 0.1 α = 0.05 α = 0.1

21 Simulation of a BAFF

22 Fish Barrier in a Quiescent Medium Bubble distribution and velocity vectors

23 Fish Barrier in a River Bubble distribution and velocity vectors

24 Streamlines colored by acceleration Quiescent Medium River

25 Fish Barrier in a Quiescent Medium Sound energy

26 Fish Barrier in a River Sound energy

27 Fish Barrier Sound energy attenuation

28 Fish Barrier Irradiance Quiescent Medium River

29 COMMENTS AND QUESTIONS